Many speaker systems are being mounted inside walls to spare the space required inside a room, and to enhance the surround-sound experience. However, in-wall speaker systems may occupy a large area of the wall they are built into. The area occupied by in-wall speaker systems may be quite significant when subwoofer speakers are part of the configuration.
In addition to the wall surface area required by in-wall mounted speakers, the speakers may transmit strong mechanical forces against the wall in which they are mounted. This is especially the case with subwoofers. The low frequencies at which subwoofers operate are more likely to cause mechanical forces that may cause the walls to vibrate.
There are other limitations. Standard wall depths limit woofer cone displacements. This leads to a need for the transducer to have a large radiating area to generate the volume displacement that is needed to create high sound pressure levels (SPL) at low frequencies. Due to the standard wall bay width, the largest typical transducer that can be mounted is a 10″woofer. Multiple 10″ woofers are typically required to obtain needed volume displacements. Each woofer added requires more and more wall area.
In view of the above, there is a need for in-wall subwoofer systems that do not occupy too much wall area, do not cause too much wall vibration during operation and do not suffer the design constraints imposed by the geometry of the wall structures.